TUBEROUS SCLEROSIS

Kidney problems such as cysts and angiomyolipomas occur in an estimated 70 to 80 percent of individuals with TSC, usually occurring between ages 15 and 30. Cysts are usually small, appear in limited numbers, and cause no serious problems. Approximately 2 percent of individuals with TSC develop large numbers of cysts in a pattern similar to polycystic kidney disease² during childhood. In these cases, kidney function is compromised and kidney failure occurs. In rare instances, the cysts may bleed, leading to blood loss and anemia.

Angiomyolipomas-benign growths consisting of fatty tissue and muscle cells-are the most common kidney lesions in TSC. These growths are seen in the majority of TSC patients, but are also found in about one of every 300 people without TSC. Angiomyolipomas caused by TSC are usually found in both kidneys and in most cases they produce no symptoms. However, they can sometimes grow so large that they cause pain or kidney failure. Bleeding from angiomyolipomas may also occur, causing both pain and weakness. If severe bleeding does not stop naturally, there may severe blood loss, resulting in profound anemia and a life-threatening drop in blood pressure, warranting urgent medical attention.

Other rare kidney problems include renal cell carcinoma, developing from an angiomyolipoma, and oncocytomas, benign tumors unique to individuals with TSC.

Three types of brain tumors are associated with TSC: cortical tubers, for which the disease is named, generally form on the surface of the brain, but may also appear in the deep areas of the brain; subependymal nodules, which form in the walls of the ventricles-the fluid-filled cavities of the brain; and giant-cell tumors (astrocytomas), a type of tumor that can grow and block the flow of fluids within the brain, causing a buildup of fluid and pressure and leading to headaches and blurred vision.

Tumors called cardiac rhabdomyomas are often found in the hearts of infants and young children with TSC. If the tumors are large or there are multiple tumors, they can block circulation and cause death. However, if they do not cause problems at birth-when in most cases they are at their largest size-they usually become smaller with time and do not affect the individual in later life.

Benign tumors called phakomas are sometimes found in the eyes of individuals with TSC, appearing as white patches on the retina. Generally they do not cause vision loss or other vision problems, but they can be used to help diagnose the disease.

Additional tumors and cysts may be found in other areas of the body, including the liver, lung, and pancreas. Bone cysts, rectal polyps, gum fibromas, and dental pits may also occur.

A wide variety of skin abnormalities may occur in individuals with TSC. Most cause no problems but are helpful in diagnosis. Some cases may cause disfigurement, necessitating treatment. The most common skin abnormalities include:

• Hypomelanic macules ("ash leaf spots"), which are white or lighter patches of skin that may appear anywhere on the body and are caused by a lack of skin pigment or melanin-the substance that gives skin its color.
• Reddish spots or bumps called facial angiofibromas (also called adenoma sebaceum), which appear on the face (sometimes resembling acne) and consist of blood vessels and fibrous tissue.
• Raised, discolored areas on the forehead called forehead plaques, which are common and unique to TSC and may help doctors diagnose the disorder.
• Areas of thick leathery, pebbly skin called shagreen patches, usually found on the lower back or nape of the neck.
• Small fleshy tumors called ungual or subungual fibromas that grow around and under the toenails or fingernails and may need to be surgically removed if they enlarge or cause bleeding. These usually appear later in life, ages 20 - 50.
• Other skin features that are not unique to individuals with TSC, including molluscum fibrosum or skin tags, which typically occur across the back of the neck and shoulders, café au lait spots or flat brown marks, andpoliosis, a tuft or patch of white hair that may appear on the scalp or eyelids.

TSC can cause seizures and varying degrees of mental disability. Seizures of all types may occur, including infantile spasms; tonic-clonic seizures (also known as grand mal seizures); or tonic, akinetic, atypical absence, myoclonic, complex partial, or generalized seizures.